In general, a circuit board includes an insulative layer, wiring patterns formed on the surface of the insulative layer, and a protective layer covering the insulative layer and the electrically conductive patterns. The circuit board electrically connects a semiconductor die to an external device and supports the semiconductor die.
A semiconductor device may include a circuit board. A semiconductor die may be mounted on the circuit board wherein a conductor may be used to electrically connect the circuit board to the semiconductor die. An underfill may be disposed in a gap formed between the circuit board and the semiconductor die to fix the semiconductor die to the circuit board. An encapsulant may be used to encapsulate the semiconductor die and the underfill. Solder balls may be welded to the circuit board and electrically connected to an external device.
During the process of forming a semiconductor device, a number of voids and air traps may form in the underfill disposed between the circuit board and the semiconductor die. These voids are a main factor of breaking the semiconductor device when the semiconductor device is put in high temperature circumstances. In other words, when the semiconductor device is put in high temperature circumstances, air or absorbed moisture in the voids expand. This expansion causes the voids to explode and thus the circuit board and the semiconductor die are electrically separated from each other.
Therefore, a need existed to provide a device and method to overcome the above problems. The device and method will reduce voids and air traps in the underfill disposed between the semiconductor device and the circuit board